"I'm about 400 pounds-months pregnant," she joked to Jay Leno on The Tonight Show Friday, Jan. 11.

The 32-year-old actress, who announced her pregnancy last November, looked positively radiant in a navy-and-black Hatch dress and Jimmy Choo heels and smiled with delight when Leno complimented her on her growing baby bump.

In the meantime, the actress explained that she's simply enjoying the pregnancy's positive effects on her body -- and mind.

"The funny thing is, [pregnancy brain] is genetically in your body so you don't have like a killer wit and abuse the kid," she said. "You kind of soak up all these wonderful hormones and you're just really nice and dumb the whole time."